# s1 = 'abc'
# names = ['tom', 'jerry', 'jack', 'rose']
# nums = (10, 20, 5, 30)
# d1 = {'name': 'nb', 'age': 20}
#
# for ch in s1:
#     print(ch)
# print('*' * 50)
# for name in names:
#     print(name)
# print('*' * 50)
# for i in nums:
#     print(i)
# print('*' * 50)
# for k in d1:
#     print(k, d1[k])

result = 0
for i in range(1, 10000001):
    result += i
print(result)






